Actinolite
| Actinolite | |
|---|---|
 (size: 6.4 cm × 4.0 cm × 1.9 cm) |
|
| General and classification | |
| other names |
Jet stone |
| chemical formula | Ca 2 (Mg, Fe) 5 [OH | Si 4 O 11 ] 2 |
|
Mineral class (and possibly department) |
Silicates and germanates - chain silicates and band silicates, calcium amphibole group |
|
System no. to Strunz and to Dana |
9.DE.10 ( 8th edition : VIII / D.05b) 66.01.03a.02 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Space group | C 2 / m (No. 12) |
| Lattice parameters |
a = 9.89 Å ; b = 18.20 Å; c = 5.31 Å β = 104.6 ° |
| Formula units | Z = 2 |
| Twinning | simple and multiple lamellar twins in parallel {100} |
| Physical Properties | |
| Mohs hardness | 5 to 6 |
| Density (g / cm 3 ) | measured: 3.03 to 3.24; calculated: [3.07] |
| Cleavage | good after {110} with transverse secretions below 56 ° and 124 ° |
| Break ; Tenacity | uneven to scalloped |
| colour | light green to black green, rarely white, gray, green or pink |
| Line color | White |
| transparency | transparent to translucent |
| shine | Glass gloss, silk gloss, matt |
| Crystal optics | |
| Refractive indices |
n α = 1.613 to 1.646 n β = 1.624 to 1.656 n γ = 1.636 to 1.666 |
| Birefringence | δ = 0.023 |
| Optical character | biaxial negative |
| Axis angle | 2V = 79 to 86 ° (measured); 78 to 82 ° (calculated) |
| Pleochroism | weak: X = light yellow, yellow green Y = light yellow green, green Z = light green, dark green blue |
The mineral actinolite ( jet stone ) is a frequently occurring and well-known rock-forming chain silicate from the group of calcium amphiboles with the chemical composition Ca 2 (Mg, Fe) 5 [OH | Si 4 O 11 ] 2 .
Actinolite crystallizes in a monoclinic crystal system and develops mostly transparent to translucent crystals up to 15 cm long with a columnar to needle-like habit , but also occurs in the form of radial, fibrous, granular and massive mineral aggregates . Also pseudomorphic after pyroxene are known.
The mineral is light green to almost black, rarely also white, gray or pink in color, but always leaves a white line on the marking board . The surfaces of visible crystals have a glass-like sheen . Actinolite, on the other hand, is matt if it is fibrous or moderately coarse, but can take on a billowing silk sheen on polished surfaces.
With a Mohs hardness of around 5 to 6, actinolite is one of the medium-hard minerals that can be scratched with a knife or a steel file.
Actinolite, the mixing member of the tremolite -Aktinolith- Ferro-actinolite - mixed batch with variable exchangeable magnesium - ions (tremolite) and iron ions (ferro-actinolite).
Etymology and history
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The name actinolite is a made-up word made up of two Greek words: ἀκτίς aktis "ray" and λίθος lithos "stone". The name refers to the mineral's often fibrous or radial appearance.
The mineral was first scientifically described in 1794 by Richard Kirwan .
classification
Already in the outdated 8th edition of the mineral classification according to Strunz , actinolite belonged to the mineral class of "silicates and germanates" and there to the department of "chain silicates and band silicates (inosilicates)" (with double chains of two (bands) [Si 4 O 11 ] 6 - ∞ ), where he named the "actinolite series" with the system no. VIII / D.05b and the other members ferro-actinolite ( ferroactinolite ) and tremolite .
In the Lapis mineral directory according to Stefan Weiß, which, out of consideration for private collectors and institutional collections, is still based on this classic system of Karl Hugo Strunz , the mineral was given the system and mineral number. VIII / F.10-20 . In the "Lapis system" this also corresponds to the section "Chain silicates and band silicates" (with double bands [Si 4 O 11 ] 6- ), where actinolite together with chromiopargasite , edenite , ferricaersutite , ferrisadanagaite , ferro-actinolite , ferro-edenite , Ferro-Ferri hornblende , Ferro-Ferritschermakit , Ferro-hornblende , Ferrokaersutit , Ferropargasit , Ferrotschermakit , Fluorocannilloit , fluoro Edenit , Fluoropargasit , Fluorotremolit , Hastingsite , Kaersutite , potassium Chlorohastingsit , potassium Chloropargasit , potassium ferro-Ferrisadanagait , potassium Ferropargasit , potassium Fluorohastingsit , potassium Fluoropargasit , Kaliumhastingsit , potassium Magnesiohastingsit , potassium Magnesiosadanagait , Kaliumpargasit , Kaliumsadanagait , Magnesio-ferrous Fluorohornblende , Magnesio-Fluorohastingsit , Magnesiohastingsit , magnesio-hornblende , Magnesiosadanagait , oxo Magnesiohastingsit , Pargasit , Parvo-Manganotremolit , Parvo-Mangano-Edenit , Sadanagait , Tremolit and Tschermakit the group de r forms “Ca 2 amphiboles”.
The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and was updated by the International Mineralogical Association (IMA) until 2009, also classifies actinolite in the category of "chain and band silicates (inosilicates)". This is, however, further subdivided according to the type of chain formation and according to whether it belongs to larger mineral families, so that the mineral is classified according to its composition in the subdivision of “chain and ribbon silicates with 2-periodic double chains, Si 4 O 11 ; Amphibole family, Klinoamphibole "is to find where it along with alumino-Ferrotschermakit , Aluminotschermakit , Cannilloit , chloro-Kaliumhastingsit , Edenit, ferric Klinoholmquistit , ferric Ferrotschermakit , Ferrikaersutit , Ferritschermakit , ferro-actinolite , Ferro-Edenit , ferrous hornblende , Ferrokaersutit , Ferropargasit , Ferrotschermakit, Fluorocannilloit, fluoro-Edenit, fluoro Magnesiohastingsit , Fluoropargasit , Fluorotremolit , Hastingsite , Joesmithit , Kaersutite, potassium Aluminosadanagait , potassium-chloro-ferrous Edenit , potassium-chloro-Pargasit , potassium ferro Ferri-Sadanagait , potassium Ferropargasit , potassium-fluoro-Hastingsite , Kaliumhastingsit , potassium Magnesiohastingsit , potassium Magnesiosadanagait , potassium Pargasit , potassium Sadanagait , Magnesiohastingsit , magnesio-hornblende, Magnesiosadanagait, Pargasit, Parvo-Mangano-Edenit, parvo Manganotremolit, Sadanagait, tremolite and Tschermakit d0ie "Ca-Klinoamphibole, tremolite group" with the system no. 9.DE.10 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , also assigns actinolite to the class of "silicates and germanates", but there in the more finely divided division of "chain silicates: double unbranched chains, W = 2". Here he is in " Group 2, calcium amphiboles " with system no. 66.01.03a to be found within the subsection of "Chain Silicates: Double unbranched chains, W = 2 amphibole configuration".
Crystal structure
Actinolite crystallizes monoclinically in the space group C 2 / m (space group no. 12) with the lattice parameters a = 9.89 Å ; b = 18.20 Å; c = 5.31 Å and β = 104.6 ° as well as 2 formula units per unit cell .
Varieties and modifications
There are currently three varieties of actinolite known:
- Amiant (also actinolite asbestos or byssolite ) - light to dark green (sometimes also blue-green), fine-haired, long-needle crystals or fine-fiber aggregates that often look like fiber mats. Amiant often appears next to epidote in a so-called paragenesis .
- Mountain leather - flat, leathery appearance
- Emeraldid or emeraldite - emerald green color due to the addition of chromium .
The nephrite is, however, a solid solution of actinolite and tremolite .
Education and Locations
Actinolite forms in metamorphic rocks such as amphibolite and slate . Accompanying minerals include albite , anthophyllite , calcite , chlorite , dolomite , epidote , glaucophane , lawsonite , pumpellyite and talc .
As a frequent mineral formation, actinolite can be found at many sites, with over 3400 sites worldwide (as of 2017) known to date. In Germany, the mineral was found in the Black Forest in Baden-Württemberg, among other places ; in Franconia and Lower Bavaria ; in the Hessian Odenwald ; in the Harz region of Lower Saxony ; near Hildfeld in North Rhine-Westphalia; in several places in the Eifel in Rhineland-Palatinate; near Treseburg in Saxony-Anhalt; near Chemnitz , in the Ore Mountains and near Zwickau in Saxony as well as near Brunsbüttel , Schönberg and Plön in Schleswig-Holstein.
In Austria, the mineral occurs mainly in Carinthia , Lower Austria , Salzburg , Styria and Tyrol and in Switzerland actinolite has so far been found in the Bernese Haslital and in several places in the cantons of Graubünden , Ticino , Uri and Valais .
Other sites are Egypt , Antarctica , Argentina , Armenia , Azerbaijan , Ethiopia , Australia , Bangladesh , Belgium , Bolivia , Brazil , Bulgaria , Chile , China , Costa Rica , Ecuador , Finland , France , Greece , Greenland , Guatemala , Guyana , India , Indonesia , Iran , Ireland , Italy , Jamaica , Japan , Cameroon , Canada , Kazakhstan , Kenya , Colombia , North and South Korea , Kosovo , Kyrgyzstan , Cuba , Madagascar , Malaysia , Mali , Morocco , Mauritania , Macedonia , Mexico , Mongolia , Namibia , Nepal , New Caledonia , New Zealand , Norway , Pakistan , Papua New Guinea , Peru , Philippines , Poland , Portugal , Puerto Rico , Rwanda , Romania , Russia , the Solomon Islands , Zambia , Saudi Arabia , Sweden , Zimbabwe , Slovakia , Spain , South Africa , Sudan , Taiwan , Thailand , Czech Republic , Turkey , Uganda , Ukraine , Hungary , Uzbekistan , Venezuela , the United Kingdom (Great Britain) and the United States of America (USA).
Actinolite could also be detected in rock samples from the Mid-Atlantic Ridge and the Central Indian Ridge .
use
Actinolite and Byssolite were mainly used as asbestos . In traditional Chinese medicine, the stone is used against impotence.
Occasionally actinolite is cut into gemstones for collectors . Clear varieties tend to have a facet cut , cloudy and, above all, fibrous varieties, on the other hand, a cabochon cut, which in addition to the silky shine can also have the visual effect of chatoyance ( cat's eye effect ).
As an asbestos mineral , actinolite ( CAS number 77536-66-4) is one of the dangerous substances whose production, placing on the market or use in the EU is restricted or prohibited in accordance with Annex XVII of the REACH regulation .
See also
literature
- Richard Kirwan: 16th species: actynolite . In: Elements of mineralogy . tape 1 , 1794, pp. 168 (English, rruff.info [PDF; 226 kB ; accessed on October 24, 2019]).
- Friedrich Klockmann : Klockmann's textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp. 726 (first edition: 1891).
- Petr Korbel, Milan Novák: Mineral Encyclopedia (= Villager Nature ). Edition Dörfler im Nebel-Verlag, Eggolsheim 2002, ISBN 978-3-89555-076-8 , p. 239 .
Web links
- Mineral Atlas: Actinolite (Wiki)
- David Barthelmy: Actinolite Mineral Data. In: webmineral.com. Retrieved October 24, 2019 .
- Actinolite search results. In: rruff.info. Database of Raman spectroscopy, X-ray diffraction and chemistry of minerals (RRUFF), accessed October 24, 2019 .
- American-Mineralogist-Crystal-Structure-Database - Actinolite. In: rruff.geo.arizona.edu. Retrieved October 24, 2019 .
Individual evidence
- ↑ a b c d e Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables. Chemical-structural Mineral Classification System . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 627 (English).
- ↑ a b c d e Actinolite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 (English, handbookofmineralogy.org [PDF; 81 kB ; accessed on October 24, 2019]).
- ↑ a b c d e f g Actinolite. In: mindat.org. Hudson Institute of Mineralogy, accessed October 24, 2019 .
- ↑ a b Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties. Status 03/2018 . 7th, completely revised and supplemented edition. Weise, Munich 2018, ISBN 978-3-921656-83-9 .
- ↑ Ernest H. Nickel, Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF 1703 kB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed October 24, 2019 .
- ↑ Hans Jürgen Rösler : Textbook of Mineralogy . 4th revised and expanded edition. German publishing house for basic industry (VEB), Leipzig 1987, ISBN 3-342-00288-3 , p. 532 .
- ↑ a b List of locations for actinolite in the Mineralienatlas and Mindat , accessed on October 24, 2019.
- ^ Walter Schumann: Precious stones and gemstones. All species and varieties in the world. 1600 unique pieces . 13th revised and expanded edition. BLV Verlags GmbH, Munich a. a. 2002, ISBN 3-405-16332-3 , pp. 236 .
- ↑ Michael RW Peters: Actinolite. In: realgems.org. January 8, 2012, Retrieved October 24, 2019 (with images of actinolite cat's eyes).
- ↑ List of restricted substances - Annex XVII of the REACH regulation: Asbestos, actinolite. In: echa.europa.eu. European Chemicals Agency (ECHA), accessed August 11, 2020 .
- ↑ Regulation (EC) No. 1907/2006 of the European Parliament and of the Council. (PDF 1.97 MB) In: eur-lex.europa.eu. December 30, 2006, p. 401 , accessed on August 12, 2020 ( Official Journal of the European Union L 396).